The present invention relates to an apparatus for screwing in set screws which can be operated by a wrench, for the connection of hollow rod elements with junction members of a framework structure, especially a space framework, in which junction members have threaded bores which are intended to receive set screws and the rod elements have end members with bores in the middle for fitting of the shanks of the set screws, of which the heads can be applied to inside shoulders of the end members for installation, and other tubular members are also provided, which extend inward from an opening in the wall of the rod element and each open axially and substantially parallel to the middle bore into their end members, in order to guide the drive members of the apparatus for screwing in.
It is known to fasten the rod elements to the junction members by means of set screws from German utility patent specification No. 83 25 005.0, in the manufacture of junction connections in framework structures of hollow rod elements and junction members. The set screws are inserted through side openings in the walls of the rod elements in tubular curved parts, which extend inwardly, axially parallel to a middle through-bore in the end member of the rod element, so that the screw shank can be forced through this middle bore and can be threaded into a threaded bore in the junction member. The curved tube parts are welded to the inside of the end members of the rod elements, and thus form one integral part with these rod elements.
For the threading in or tightening of a set screw guided in through such a tubular part, a screwdriver with a Phillips head is used, which can likewise be used for the threading in the tubular part. Furthermore, even before the assembly of the framework structure in the tubular guide parts, to arrange the stop or set screws so that they cannot be lost, it is already known to provide friction elements on the heads of these stop screws, which cooperate with the inside wall of the tubular guide parts, in order thus to prevent undesired release of the screws from the tubular guide parts. The tubular guide parts also serve to hold the stop screws.
The drawback of this known configuration resides particularly in that the rod elements are made more expensive by use of the tubular guide parts welded on both ends thereof, and during the assembly of the framework structure there is no possibility of rapidly and safely determining that the stop or set screws are also being threaded properly into the junction, in order to guarantee the required proper rod connection.
It is also already known, from German utility patent specification No. 83 04 465.5, to provide peepholes in the end members of the rod elements, in order to be able to determine whether the stop screws have also indeed been threaded to the required degree of threading. Such peepholes, however, of the size required for this monitoring, weaken the rod elements and make them even more expensive.